Webmaster prerequisites: Common knowledge about VM applications

What is a virtual host?
Virtual hosts use special hardware and software technologies to divide a server host running on the internet into a "virtual" host. Each virtual host has an independent domain name or IP address, it has complete Internet server (WWW, FTP, Email, and so on) functions. Virtual hosts are completely independent of each other and can be managed by users. In the outside world, each VM is exactly the same as the master.


Does the performance of each virtual host decrease as resources are allocated to several virtual hosts?
Theoretically, this is the case. However, because the computers used as virtual hosts use computers with high performance, a host can support a certain number of virtual hosts. When this quantity is exceeded, users will feel the performance decline. If configured properly and over-high-speed lines are used, the performance of virtual hosts is usually better than that of independent hosts connected by low-speed lines (such as 256 K and 1.544 M. In a competitive environment, most providers will not increase the number of virtual hosts and sacrifice the interests of users in pursuit of extreme profits. Because in that case, you will lose your "God ". However, you still need to carefully select and compare various providers. Bluehost, a foreign virtual host provider recommended on this site, provides good configuration.

What is the cost of a VM?
The emergence of virtual hosts is a major contribution to Internet technology and a good news for Internet users. Because multiple virtual hosts share the resources of a real host, the hardware cost, network maintenance cost, and communication line cost for each user are greatly reduced. Internet is truly an affordable network for everyone! In contrast, foreign virtual hosts are more mature and provide better and more stable services. For example, the cost of bluehost is only $7 per month, but it provides 50 GB of host space and domain names.
What operating system does a VM use?

Currently, the most widely used operating systems are Linux and Microsoft Windows. Both have their own strengths. Generally, foreign VM vendors prefer Linux OS hosts, which support php/perl/python/ruby/CGI (all programs except asp; windows OS hosts support almost all programs, but generally linux/unix virtual hosts are cheaper, because linux/php/perl/mysql/apache are free programs, windows machines are generally used to run asp /. net, so the price is slightly higher due to license reasons. How many virtual hosts can be supported on a single host?
This depends on the host's CPU, memory capacity, I/O channel speed, hard disk space, and other performance. Generally, it can support 80 ~ There are even more than 100 virtual hosts, but the more hosts you put above, the more affected the performance.

Can I upload or download files to or from my VM through FTP?

Yes. Generally, files in any format can be placed in the specified directory of your VM for users to download. For upload, you must have the required permissions to upload files to ensure security. Foreign virtual hosts even provide anonymous ftp access services. There are more restrictions in China.